Above and Beyond

Designed to measure ozone, a Ball instrument is contributing to long-term climate and air quality measurements.

On board NASA’s Suomi National Polar-orbiting Partnership (Suomi-NPP) spacecraft, the Ozone Mapping and Profiler Suite (OMPS) is an instrument designed to measure ozone and how ozone concentration varies with altitude. But it’s doing much more. OMPS is helping forecasters predict extreme wind events, track the migration of smoke, pollution, volcanic ash and meteor debris, and is giving scientists a better understanding of higher altitude dynamics.

“OMPS collects data across a wide range of the electromagnetic spectrum,” explained Sarah Lipscy, Ball’s OMPS deputy program manager and instrument scientist. “It’s a three-part hyperspectral instrument, with two downward-looking or nadir spectrometers, and a limb profiler spectrometer. The nadir instruments map global ozone and measure the distribution of ozone in the stratosphere, and the limb profiler measures ozone in the stratosphere and upper troposphere.”

Up in the airIn addition to measuring ozone, OMPS’ downward-looking nadir spectrometers are identifying and tracking smoke and pollution at altitudes above about 12 km (7.5 miles). “This type of mapping measures the aerosol index, which detects fine airborne particles that absorb ultraviolet light,” explained Lipscy. “That’s how OMPS tracked the dust and smoke from California’s Rim Fire near Yosemite National Park in August 2013 and mapped migration patterns that impacted air quality hundreds of miles away.”

From the perspective of a climate scientist, the most promising capability of OMPS is to continue stratospheric aerosol measurements. The Stratospheric Aerosol & Gas Experiment (SAGE) III on the International Space Station, due to launch in 2016, is designed to measure aerosols, ozone, water vapor and other gases in the atmosphere. When SAGE finishes its mission, OMPS will be the only U.S. instrument measuring global coverage of total aerosol loading, which will increase the completeness of long-term climate measurements.
In addition to its aerosol measuring capabilities, OMPS can help predict extreme, non-storm related wind events that are linked to stratospheric intrusions. These ozone intrusions occur when high altitude ozone-rich air plunges down to the ground from high in the stratosphere. Ozone intrusion data can help predict weather that is not part of a storm and provide forecasters with critical information about how air moves between the stratosphere and troposphere. OMPS data also improves air quality models because it correlates with data from other sources on global particulates in the atmosphere.

Erupting fire and ashOMPS tracks sulfur dioxide (SO2) generated from volcanoes and man-made sources and nitrogen dioxide (NO2) from coal-fired power plants and other fossil fuel sources once these gases make their way to the upper atmosphere. These gases are characterized with high precision by OMPS readings, and daily maps chart the evolution of such pollution. When the Joint Polar-orbiting Satellite System-1 spacecraft launches in 2017, the next-generation OMPS instrument onboard will be able to deliver even higher resolution sulfur and nitrogen dioxide data.

Atmospheric sulfur dioxide from volcanoes observed by OMPS correlates well with the SO2 data from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite. OMPS improves on OMI by providing full global coverage and delivering high spatial resolution data. “OMPS’ data has also been validated with ground-based measurements,” said Lipscy. “This provides near real-time data to detect and monitor volcanic plumes that can endanger aircraft.”

Air traffic controller alerts
Volcanic eruptions eject large amounts of ash and sulfur dioxide into the atmosphere which reach the cruising altitude of commercial aircraft. When jets fly through a volcanic ash cloud, it can severely damage the aircraft, clog sensors, limit visibility, and severely scratch, or 'sandblast’ critical aircraft parts. Ash particles that enter jet engines can cause engine failure. Every year there are about 60 volcanic eruptions. Since ground-based monitoring is carried out on only a limited number of volcanoes, observations of sulfur dioxide and aerosols from satellite measurements in near-real time can provide useful complementary information to assess the global impacts of volcanic eruptions on air traffic control operations and public safety.

OMPS is now part of the European Space Agency’s Support for Aviation Control Service which delivers SO2 alerts to air traffic controllers, volcano observatories, health care organizations and scientists, among others. OMPS data is currently being used to complement OMI/Aura data in software used to determine flight routes. Aviation forecasters also rely on direct readouts from OMPS passes during Suomi-NPP’s orbit. They gather a swath of raw data every 1.5 hours and process it to get near real-time information.

Higher altitude dynamicsThe OMPS limb profiler provides tracking data for upper atmosphere dynamics, giving forecasters insight into the behavior of winds at high altitudes, which can provide clues to future weather patterns. A new capability for OMPS was discovered by a scientist at NASA Goddard Space Flight Center whose hometown was Chelyabinsk, Russia, which was hit by a meteor on February 15, 2013. Looking to see if the OMPS limb profiler picked up debris from the impact, he discovered it showed above normal levels of meteor debris at high altitudes (30-45 km/18.6-27.9 miles). OMPS data showed that the plume had circumnavigated the globe and a month later, a new dust structure appeared at lower latitudes, allowing the tracking of meteor debris on a scale never before done.

OMPS data are also being used to monitor noctilucent, or Polar Mesospheric Clouds (PMCs), which consist of water vapor frozen into ice crystals lit by the setting or rising sun. PMCs show up on OMPS limb data as artifacts, which ozone scientists usually remove. However, climate scientists and meteorologists welcome this data because it allows them to characterize, catalog and observe PMC trends year over year.

Noctilucent clouds form at 76-85 km (46.6-52.8 miles) above the Earth’s surface in the mesosphere. By helping us better understand the relationship between stratospheric and mesospheric interactions, OMPS may be able to refine Numerical Weather Prediction models and noctilucent clouds may be a good place to start. Since PMCs are a relatively newly categorized phenomenon, forecasters are in a discovery phase about what causes them to form. Suggestions include dust from meteors, rocket exhaust and greenhouse gas concentrations.
OMPS data gathered on these cloud formations can be used to monitor trends in atmospheric and global climate change.

Targeted UV IndexesOMPS measurements have the ability to make UV Index forecasts much more accurate. The UV Index measures the amount of radiation reaching the Earth’s surface at a location and depends on the latitude, altitude, time of year, time of day, weather conditions, surface conditions and the thickness of the stratospheric ozone layer.

UV Index forecasts based on ozone forecasts will be improved by OMPS’ higher spatial resolution. The current instrument can indicate the amount of ozone in the atmosphere within a 50 km (31 mile) square area, accounting for UV Index differences for cities just 70 miles apart.

“With the new OMPS instrument due to launch on the Joint Polar Satellite System-1 (JPSS-1) in 2017, the index will be measured over a 12km (7.4 mile) area, so areas north and south of the same city may have different UV indexes due to the improved instrument resolution,” said Lipscy.

OMPS’ data may prove to be key to the future of weather forecasts and understanding of air pollution patterns. Out of the 51 scientific papers published on OMPS data since Suomi-NPP launched in 2011, more than half focused on non-ozone related data collected by the instrument. OMPS’ spatial resolution and stability of calibration has allowed it to track new data and contribute to weather forecasts and air quality assessments the world over.